At the present time I have an eight port Infiniband switch that is in full use between eight servers. I am looking to add a few servers soon but I won't have enough ports on the switch to do this.

My question is, will I have to purchase a switch that has more ports or can I buy a second switch of the same size and daisy chain them together? I understand the bandwidth implications between the two switches, but I'm just wondering if it's even possible to do this with Infiniband.

You can chain the InfiniBand switches. You could chain, link, loop, cross link, many, many switches in an InfiniBand fabric.

If you have some InfiniBand switches with embedded Subnet Manager, you will have to configure the switches so that you have only one Subnet Manager, or to configure them to cooperate.

As you mention, the bandwidth will be limited if your communications pattern require exchange between the two switches. Take great care of the locality of each node to group highly related nodes on the same switch.

If you have more than 2 switches, you can create advanced topology to improve the bandwidth and latency, tailored to your needs.

But if you have one single bigger switch to support few more nodes, it will be indeed simpler and better.

[Additionally you could investigate reliability issues: what happen if the switch is gone ...]

Regards.

1 members found this post helpful.

Thanks! Very helpful answer, I appreciate it.